Data analysis is used to gain insight into the information being analyzed and to provide tools used in the evaluation of people, animals, equipment, etc.
One tool used in the evaluation of a person's health is the reference interval. A reference interval is a range of values used in making decisions, such as medical diagnoses, therapeutic management decisions or other physiological assessments. A given reference interval is compared to a result produced from, for instance, a laboratory test performed on a person. If the result falls within the reference interval, then the result is considered within normal range. On the other hand, if the result falls outside of the interval, then the result is considered abnormal.
The clinical laboratory reference interval is the most widely used decision making tool in medicine. The National Committee on Clinical Laboratory Standards (NCCLS) recommends establishing health-associated reference intervals based on age, gender, race and stage of pregnancy, where appropriate. The National Committee on Clinical Laboratory Standards recommends that each reference interval be established by in-house testing (≧120 individuals/interval) or by validated transference of reference intervals from literature or manufacturer. The transference of reference intervals is the predominate practice. The NCCLS guidelines for determination or transference of reference intervals focus on non-clinical reference individuals. One embodiment of the NCCLS guidelines is described in “How to Define and Determine Reference Intervals in the Clinical Laboratory; Approved Guideline—Second Edition,” NCCLS, C28-A2, Vol. 20, No. 13, which is hereby incorporated herein by reference in its entirety.
Compliance with the National Committee on Clinical Laboratory Standards is challenging for all hospitals, commercial and practice-based clinical laboratories.